314 research outputs found
5D fuzzball geometries and 4D polar states
We analyze the map between a class of `fuzzball' solutions in five dimensions
and four-dimensional multicentered solutions under the 4D-5D connection, and
interpret the resulting configurations in the framework of Denef and Moore. In
five dimensions, we consider Kaluza-Klein monopole supertubes with circular
profile which represent microstates of a small black ring. The resulting
four-dimensional configurations are, in a suitable duality frame, polar states
consisting of stacks of D6 and anti-D6 branes with flux. We argue that these
four-dimensional configurations represent zero-entropy constituents of a
2-centered configuration where one of the centers is a small black hole. We
also discuss how spectral flow transformations in five dimensions, leading to
configurations with momentum, give rise to four-dimensional D6 anti-D6 polar
configurations with different flux distributions at the centers.Comment: Latex, 36 pages, 2 figures. v2: typos corrected, references added,
published versio
Evidence-based health care policy in reimbursement decisions : lessons from a series of six equivocal case-studies
Context: Health care technological evolution through new drugs, implants and other interventions is a key driver of healthcare spending. Policy makers are currently challenged to strengthen the evidence for and cost-effectiveness of reimbursement decisions, while not reducing the capacity for real innovations. This article examines six cases of reimbursement decision making at the national health insurance authority in Belgium, with outcomes that were contested from an evidence-based perspective in scientific or public media.
Methods: In depth interviews with key stakeholders based on the adapted framework of Davies allowed us to identify the relative impact of clinical and health economic evidence; experience, expertise & judgment; financial impact & resources; values, ideology & political beliefs; habit & tradition; lobbyists & pressure groups; pragmatics & contingencies; media attention; and adoption from other payers & countries.
Findings: Evidence was not the sole criterion on which reimbursement decisions were based. Across six equivocal cases numerous other criteria were perceived to influence reimbursement policy. These included other considerations that stakeholders deemed crucial in this area, such as taking into account the cost to the patient, and managing crisis scenarios. However, negative impacts were also reported, in the form of bypassing regular procedures unnecessarily, dominance of an opinion leader, using information selectively, and influential conflicts of interest.
Conclusions: 'Evidence' and 'negotiation' are both essential inputs of reimbursement policy. Yet, purposely selected equivocal cases in Belgium provide a rich source to learn from and to improve the interaction between both. We formulated policy recommendations to reconcile the impact of all factors identified. A more systematic approach to reimburse new care may be one of many instruments to resolve the budgetary crisis in health care in other countries as well, by separating what is truly innovative and value for money from additional 'waste'
Some thoughts about matrix coordinate transformations
Matrix coordinate transformations are defined as substitution operators
without requiring an ordering prescription or an inclusion function from the
Abelian coordinate transformations. We construct transforming objects mimicking
most of the properties of tensors. We point out some problems with the matrix
generalization of contravariant vectors. We suggest to use the substitution
operators to search for an inclusion function.Comment: LaTeX, 12 page
How to reform western care payment systems according to physicians, policy makers, healthcare executives and researchers: a discrete choice experiment
Background: Many developed countries are reforming healthcare payment systems in order to limit costs and improve clinical outcomes. Knowledge on how different groups of professional stakeholders trade off the merits and downsides of healthcare payment systems is limited.
Methods: Using a discrete choice experiment we asked a sample of physicians, policy makers, healthcare executives and researchers from Canada, Europe, Oceania, and the United States to choose between profiles of hypothetical outcomes on eleven healthcare performance objectives which may arise from a healthcare payment system reform. We used a Bayesian D-optimal design with partial profiles, which enables studying a large number of attributes, i.e. the eleven performance objectives, in the experiment.
Results: Our findings suggest that (a) moving from current payment systems to a value-based system is supported by physicians, despite an income trade-off, if effectiveness and long term cost containment improve. (b) Physicians would gain in terms of overall objective fulfillment in Eastern Europe and the US, but not in Canada, Oceania and Western Europe. Finally, (c) such payment reform more closely aligns the overall fulfillment of objectives between stakeholders such as physicians versus healthcare executives.
Conclusions: Although the findings should be interpreted with caution due to the potential selection effects of participants, it seems that the value driven nature of newly proposed and/or introduced care payment reforms is more closely aligned with what stakeholders favor in some health systems, but not in others. Future studies, including the use of random samples, should examine the contextual factors that explain such differences in values and buy-in.
JEL classification: C90, C99, E61, I11, I18, O5
Healthcare payment reforms across western countries on three continents: Lessons from stakeholder preferences when asked to rate the supportiveness for fulfilling patientsâ needs
International audienceTo test the hypothesis that care typology-being complex and highly unpredictable versus being clear-cut and highly predictable-guides healthcare payment preferences of physicians, policy makers, healthcare executives, and researchers. We collected survey data from 942 stakeholders across Canada, Europe, Oceania, and the United States. A total of 48 international societies invited their members to participate in our study. Study design Cross-sectional analysis of stakeholder survey data linked to four scenarios of care typology: primary prevention, trial-and-error care, standard care and network care. Principal findings We identified two âextremesâ: (1) dominant preferences of physicians, who embraced fee for service (FFS), even when this precludes the advantages of other payment systems associated with a minimal risk of harm (OR 1.85 for primary prevention; OR 1.89 for standard care, compared to non-physicians); and (2) the dominant preferences of healthcare executives and researchers, who supported quality bonus or adjustment (OR 1.92) and capitation (OR 2.05), respectively, even when these could cause harm. Conclusions Based on exploratory findings, we can cautiously state that payment reform will prove to be difficult as long as physicians, healthcare executives, and researchers misalign payment systems with the nature of care. Replication studies are needed to (dis)confirm our findings within representative subsamples per area and stakeholder grou
Voordelen, nadelen en haalbaarheid van het invoeren van âPay for Qualityâ programmaâs in BelgiĂ«
Black Hole Meiosis
The enumeration of BPS bound states in string theory needs refinement.
Studying partition functions of particles made from D-branes wrapped on
algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow
trees, we extend the method for computing a refined BPS index, arXiv:0810.4301.
For certain D-particles, a finite number of microstates, namely polar states,
exclusively realized as bound states, determine an entire partition function
(elliptic genus). This underlines their crucial importance: one might call them
the `chromosomes' of a D-particle or a black hole. As polar states also can be
affected by our refinement, previous predictions on elliptic genera are
modified. This can be metaphorically interpreted as `crossing-over in the
meiosis of a D-particle'. Our results improve on hep-th/0702012, provide
non-trivial evidence for a strong split attractor flow tree conjecture, and
thus suggest that we indeed exhaust the BPS spectrum. In the D-brane
description of a bound state, the necessity for refinement results from the
fact that tachyonic strings split up constituent states into `generic' and
`special' states. These are enumerated separately by topological invariants,
which turn out to be partitions of Donaldson-Thomas invariants. As modular
predictions provide a check on many of our results, we have compelling evidence
that our computations are correct.Comment: 46 pages, 8 figures. v2: minor changes. v3: minor changes and
reference adde
Healthcare payment reforms across western countries on three continents: Lessons from stakeholder preferences when asked to rate the supportiveness for fulfilling patientsâ needs
Effects of clinical pathways in the joint replacement: a meta-analysis
<p>Abstract</p> <p>Background</p> <p>A meta-analysis was performed to evaluate the use of clinical pathways for hip and knee joint replacements when compared with standard medical care. The impact of clinical pathways was evaluated assessing the major outcomes of in-hospital hip and knee joint replacement processes: postoperative complications, number of patients discharged at home, length of in-hospital stay and direct costs.</p> <p>Methods</p> <p>Medline, Cinahl, Embase and the Cochrane Central Register of Controlled Trials were searched. The search was performed from 1975 to 2007. Each study was assessed independently by two reviewers. The assessment of methodological quality of the included studies was based on the Jadad methodological approach and on the New Castle Ottawa Scale. Data analysis abided by the guidelines set out by The Cochrane Collaboration regarding statistical methods. Meta-analyses were performed using RevMan software, version 4.2.</p> <p>Results</p> <p>Twenty-two studies met the study inclusion criteria and were included in the meta-analysis for a total sample of 6,316 patients. The aggregate overall results showed significantly fewer patients suffering postoperative complications in the clinical pathways group when compared with the standard care group. A shorter length of stay in the clinical pathway group was also observed and lower costs during hospital stay were associated with the use of the clinical pathways. No significant differences were found in the rates of discharge to home.</p> <p>Conclusion</p> <p>The results of this meta-analysis show that clinical pathways can significantly improve the quality of care even if it is not possible to conclude that the implementation of clinical pathways is a cost-effective process, because none of the included studies analysed the cost of the development and implementation of the pathways. Based on the results we assume that pathways have impact on the organisation of care if the care process is structured in a standardised way, teams critically analyse the actual organisation of the process and the multidisciplinary team is highly involved in the re-organisation. Further studies should focus on the evaluation of pathways as complex interventions to help to understand which mechanisms within the clinical pathways can really improve the quality of care. With the need for knee and hip joint replacement on the rise, the use of clinical pathways might contribute to better quality of care and cost-effectiveness.</p
- âŠ